Defect compensation of nitrogen-containing diamond film via boron doping

Diamond film with low impurity and defect density is crucial for detector fabrication. However, high-speed growth with nitrogen inevitably introduces impurities and related defects into the diamond film. Boron doping was employed as a secondary treatment to suppress these impurities and compensate the defects using microwave plasma chemical vapor deposition with different B/C ratios. Compared to the CVD seed, the treated sample showed a reduced full width at half maximum of the Raman peak and surface roughness Ra. PL spectra revealed a significant decrease in the intensity of NV− and Si-V− centers. FTIR spectra indicated that the A-form nitrogen peak nearly disappeared. An appropriate compensation was achieved with a B/C ratio of 2500 ppm where n-type conductivity converted to p-type at a low CH4/H2 ratio. As a result, the leakage currents were reduced by approximately three orders of magnitude in the I-V test.